<div class="root">
  <div class="toolbar">
    <span class="command-btn">B</span>
    <span class="command-btn">I</span>
    <span class="command-btn">D</span>
    <span class="command-btn">U</span>
    <span class="command-btn">H1</span>
    <span class="command-btn">H2</span>
    <span class="command-btn">H3</span>
    <span class="command-btn">H4</span>
    <span class="command-btn">P</span>
    <span class="command-btn">sub</span>
    <span class="command-btn">code</span>
  </div>
  <div class="textarea" contenteditable="true"></div>
</div>
